Note, auto support for metal assets will be added soon (Swift 5.3). For now you need to link the Metal libraries in your app.
Get the latest Metal library for your platform here and add it to your bundle.
Then in AppDelegate.swift, import PixelKit, and in application(_:didFinishLaunchingWithOptions:), add the following:

CocoaPods:

CocoaPods is a dependency manager for Cocoa projects. For usage and installation instructions, visit their website. To integrate PixelKit into your Xcode project using CocoaPods, specify it in your Podfile:

pod 'PixelKit', '~> 1.0.0'

And import:

import PixelKit

Note that PixelKit only have simulator support in Xcode 11 for iOS 13 on macOS Catalina. Metal for iOS can only run on a physical device in Xcode 10 or below.

To gain camera access, on macOS, check Camera in the App Sandbox in your Xcode project settings under Capabilities.

Coordinate Space

PixelKit coordinate space is normailzed to the vertical axis (1.0 in height) with the origin (0.0, 0.0) in the center.
Note that compared to native UIKit views the vertical axis is flipped and origin is moved, this is more convinent when working with graphics is PixelKit.
A full rotation is defined by 1.0